The present invention relates to a variable-capacity swash-plate type compressor, which is used in vehicle air-conditioning apparatuses.
As a conventional variable-capacity swash-plate type compressor (hereinafter, simply referred to as a compressor), a compressor has been known which is disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 7-91,366. In this compressor, as illustrated in FIG. 11, cylinder bores 8 are formed in a cylinder block 1, inlet chambers 30 and an outlet chamber 31 are formed in a rear housing 3, and a crank chamber 5 is formed in the front housing 2. These front housing 2, cylinder block 1 and rear housing 3 are bonded with each other to constitute a housing.
In the crank chamber 5, a driving shaft 6 is held rotatably by the front housing 2 and the cylinder block 1 by way of bearings 7a, 7b. Onto the driving shaft 6, in-between the front housing 2, a rotor 10 is supported synchronously rotatably by way of a bearing 2a, and, in-between the rotor 10, a swash plate 11 is supported synchronously rotatably by way of a pair of hinge mechanisms K, K. The respective hinge mechanisms K, K include a supporting arm 17, which protrudes rearward from the rotor 10 and in which a guide hole 17a is drilled through, and a guide pin 16, which is fastened to a bracket 15, being disposed integrally and protrudingly in front of the swash plate 11, and which has a sphere portion 16a, being fitted idly into the guide hole 17a reciprocatably, at the leading end. The respective hinge mechanisms K, K are disposed oppositely so as to cross over the top-dead-center position T of the swash plate 11. Between the rotor 10 and the swash plate 11, an inclination-angle reducing spring 12 is interposed, and the inclination-angle reducing spring 12 urges the swash plate 11 toward the rear housing 3 in such a direction that the inclination angle reduces from the maximum inclination angle to the minimum inclination angle.
Further, in the swash plate 11, a through hole 20, into which the driving shaft 6 is fitted, is drilled through. This through hole 20, as illustrated in FIG. 12, is formed so as to permit an inclination-angle displacement of the swash plate 11 over an entire control range about a swing-shaft center Y, which is set beyond a side of the driving shaft 6, side which faces the hinge mechanisms, K, K, while interposing a shaft center X of the driving shaft 6 therebetween. Namely, this swash plate 11, as illustrated in FIG. 11, is inhibited from further inclining in the inclination-angle reducing direction by contacting a rear end surface 11b, which is formed as a concaved-shape at the trailing end of the through hole 20, with a circlip 13, which is engaged with the driving shaft 6, when the inclination-angle reducing spring 12 is put into the most extended state. On the contrary, the swash plate 11 is inhibited from further inclining in the inclination-angle enlarging direction by contacting a front end surface 11a, which is formed at the bottom in a slanted manner, with a rear end surface 10a of the rotor 10 when the inclination-angle reducing spring is put into the most contracted state.
And, pistons 9 are engaged with this swash plate 11 by way of a pair of shoes 14, which serve as a connecting mechanism for transforming the to-and-fro swinging movement according to the inclination angle into the reciprocating movements, and the respective pistons 9 are accommodated in the respective cylinder bores 8.
Between the cylinder block 1 and the rear housing 3, a valve plate 4, etc., are interposed. In the valve plate 4, inlet ports 32 and outlet ports 33 are formed to open correspondingly to the respective cylinder bores 8, and compression chambers, which are formed between the valve plate 4 and the pistons 9, are communicated with inlet chambers 30 and an outlet chamber 31 by way of the inlet ports 32 and the outlet ports 33. On the respective inlet ports 32, inlet valves, not shown, are disposed which open and close the inlet ports 32 in accordance with the reciprocate movements of the pistons 9, and, on the respective outlet ports 33, outlet valves, not shown, are disposed which open and close the outlet ports 33 in accordance with the reciprocate movements of the pistons 9 while being regulated by retainers 34.
Moreover, in the cylinder block 1, an air-bleeding passage, not shown, is disposed which communicates the crank chamber 5 with the inlet chambers 30, and this air-bleeding passage is opened and closed by a control valve, not shown.
In this compressor, when the rotor 10 and the swash plate 11 are rotated at a predetermined angle, accompanied by the driving of the driving shaft 6, the pistons 9 are reciprocated in the cylinder bores 8. Thus, a refrigerant gas is sucked from the inlet chambers 30 into the compression chamber, and, after the refrigerant gas is compressed, it is discharged into the outlet chamber 31. And, the inclination angle of the swash plate 11 is displaced by adjusting the pressure in the crank chamber 5 by the control valve, and thereby the outlet capacity of the refrigerant gas, which is discharged into the outlet chamber 31, is controlled.
At this moment, as illustrated in FIG. 12, when the swash plate 11 is put into the maximum inclination angle, a front lower surface 20c and rear upper surface 20d of the through hole 20 do not contact with a peripheral surface of the driving shaft 6. Moreover, when the swash plate 11 is put into the minimum inclination angle, a rear lower surface 20e and front upper surface 20f of the through hole 20 do not contact with the peripheral surface of the driving shaft 6. Namely, the through hole 20 does not define the maximum inclination angle and the minimum inclination angle, and the clearance between the through hole 20 and the driving shaft 6 is enlarged.
And, in this compressor, since a supporting portion 20b in the through hole 20 is formed as an arc shape, the peripheral surface of the driving shaft 6 always keeps a linear contact with the supporting portion 20b, and the supporting portion 20b is less likely to be worn. Moreover, since the moments, which result from the compression reaction force, etc., can be received almost by the pair of hinge mechanisms K, K, regulatory surfaces 20a, 20a of the swash plate 11 are also less likely to be worn. Hence, in this compressor, the inclination angle of the swash plate 11 is secured reliably, and a good durability can be effected.
However, not only in the swash-plate type compressor set forth in the aforementioned publication, but also in variable-capacity swash-plate type compressors involving wobble type ones widely, in a case where a compression operation is not carried out or in a case where a compression operation is carried out at a small outlet capacity regarded as zero substantially, it has been found out that such drawbacks take place in that noises and vibrations arise and colliding portions wear when a large vibration is applied from the exterior, drawbacks which result from the clearance of the inclination-angle variable swash plate.
Namely, in the variable-capacity swash-plate type compressors involving wobble type ones widely, the swash plate is supported by providing clearances of certain extent in-between the other members, such as the driving shaft, a sleeve, etc., so that the postures and positions, accompanied by the inclination-angle displacement, can be varied, and thereby the swash plate varies the inclination angle so that the variable capacity is realized.
Here, in a case where the compressor carries out a compression operation at a large outlet capacity, since a compression load acts onto the swash plate from the pistons, regardless of the clearances in-between the other members, the swash plate keeps contacting with the other members by the compression load at the predetermined positions. Hence, in this case, even when a large vibration is applied from the exterior, since the swash plate does not collide with the other members repeatedly, noises, etc., do not arise.
However, in the case where the compression operation is not carried out or in the case where the compression is carried out at a small outlet capacity regarded as zero substantially, the compression load does not act onto the swash plate, or hardly acts thereonto, if a large vibration is applied from the exterior, since the swash plate collides with the other members repeatedly, noises, etc., arise.
In particular, in the swash-plate type compressor set forth in the aforementioned publication, since the driving shaft, which is fitted into the through hole of the swash plate, can be the aforementioned other member, and since it is comparatively difficult to form the through hole with a high accuracy, this tendency is apparent.
The present invention has been done in view of the aforementioned conventional circumstances. In a variable-capacity swash-plate type compressor involving wobble type ones widely, it is an object, without obstructing the inclination-angle displacement of the swash plate accompanied by the variable capacity, to inhibit the drawbacks, such as the noises, etc., in the case where the compression operation is not carried out or in the case where the compression operation is carried out at a small outlet capacity regarded as 0 substantially.
A variable-capacity swash-plate type compressor according to the present invention, which is constituted so that a crank chamber, inlet chambers, an outlet chamber and cylinder bores connected therewith are demarcated and formed in a housing, so that pistons are accommodated reciprocatably in the respective cylinder bores, respectively, so that a rotor, positioned in said crank chamber, is supported synchronously rotatably onto a driving shaft, supported by the housing, and a swash plate, connected thereto by way of the rotor and a hinge mechanism, is fitted therewith so as to make an inclination angle variable, so that a connecting mechanism, transforming a to-and-fro swinging movement of said swash plate into reciprocating movements of the respective pistons, is interposed between the swash plate and said pistons, and so that the inclination angle of said swash plate is controlled by a pressure in said crank chamber so as to vary an outlet capacity, wherein it is characterized in that an aligning member, which contacts with said swash plate to align said swash plate, is interposed.
In the present compressor, since the aligning member contacts with the swash plate to align the swash plate, the clearances, which the swash plate has in-between the other members, such as the driving shaft, a sleeve, etc., are absorbed while making the variations of the postures and positions, accompanied by the inclination-angle displacement of the swash plate, possible. Hence, in the case where this compressor does not carry out the compression operation, or in the case where it carries out the compression operation at a small outlet capacity regarded as zero substantially, even when a large vibration is applied from the exterior, since the swash plate does not collide with the other members repeatedly, noises and vibrations do not arise, and the wears at the colliding portions are less likely to occur.
Accordingly, the present compressor can, without obstructing the inclination-angle displacement of Lhe swash plate accompanied by the variable capacity, inhibit the drawbacks, such as the noises, etc., in the case where it does not carry out the compression operation or in the case where it carries out the compression operation at a small outlet capacity regarded as 0 substantially.
As the aligning member, in a case where the driving shaft is the other member, namely, in a case where the swash plate contacts directly with the driving shaft, it is possible to employ a washer, which is fitted with the driving shaft to fill up the clearance between the swash plate and the driving shaft. Alternatively, in a case where a sleeve, which is fitted with the driving shaft, is the other member, namely, in a case where the swash plate contacts directly with the sleeve, it is possible to employ a washer, which fills up the clearance between the swash plate and the sleeve.
Further, it is suitable to provide the present compressor with an urging means, which urges this aligning member onto a swash-plate side. This is because the aligning member is moved onto the swash-plate side by the urging force of the urging means so that it is likely to fill up the clearances between the swash plate and the other members.
Furthermore, it is suitable that said aligning member is disposed between the rotor and the swash plate, and that said urging means is an inclination-angle reducing spring, which urges the swash plate in such a direction that the inclination angle is reduced from the maximum inclination angle to the minimum inclination angle.
By utilizing the inclination-angle reducing spring, it is not needed to especially dispose an urging means, which urges the aligning member only, and it is possible to realize the reduction of the product cost by reducing the number of the component parts.
Moreover, it is suitable that said aligning member is disposed on an opposite side of the rotor with respect to the swash plate, and that said urging means is a return spring, which urges the swash plate in such a direction that the inclination angle is enlarged from the minimum inclination angle to a limit angle or more.
By utilizing the return spring, it is not needed to especially dispose an urging means, which urges the aligning member only, and it is possible to realize the reduction of the product cost by reducing the number of the component parts. Note that, in this case, the aligning member is disposed on an opposite side with respect to the case where the aforementioned inclination-angle reducing spring is utilized.
In addition, it is suitable that said aligning member includes a first aligning member, which is disposed between the rotor and the swash plate, and a second aligning member, which is disposed on an opposite side of the rotor with respect to the swash plate, and that said urging means includes an inclination-angle reducing spring, which urges the first aligning member in such a direction that the inclination angle of the swash plate is reduced from the maximum inclination angle to the minimum inclination angle, and a return spring, which urges the second aligning member in such a direction that the inclination angle of the swash plate is enlarged from the minimum inclination angle to a limit angle or more.
In this case, both of the aforementioned cases are combined. By aligning the swash plate from both of the front and rear sides, without obstructing the inclination-angle displacement of the swash plate accompanied by the variable capacity, it is possible to further effectively prevent the drawbacks, such as the noises, etc., when the compression operation is not carried out or when the compression operation is carried out at a small capacity regarded as 0 substantially.
It is suitable that at least one portion, which is selected from the group consisting of a portion with which said swash plate contacts said aligning member and a portion with which said aligning member contacts said swash plate, is formed as a minor-diameter tapered surface on an inner side of the swash plate.
Thus, a minor-diameter side of the tapered surface is positioned on an inner side of the swash plate, and consequently it is likely to fill up the clearances between the swash plate and the other members.
In a case where such a tapered surface is formed on the portion with which the swash plate contacts the aligning member, it is possible to form it by using a cutting tool, which has a taper-processed surface at the leading end, so as to advance the cutting tool in two directions with respect to the swash plate, or so as to gently swing the cutting tool or the swash plate between the two directions.
In a case where both of the portion with which the swash plate contacts the aligning member and the portion with which the aligning member contacts the swash plate are formed as such tapered surfaces, it is preferred that they are formed so as to have an equal opening angle. Thus, their tapered surfaces contact superficially with each other, and accordingly it is possible to reduce the wear between both of them.
By the way, it is not necessarily easy to process both of them so as to form the tapered surfaces having an equal opening angle. On the other hand, even if the both of them are processed so as to form the tapered surfaces having an equal opening angle, after a compressor is assembled, it is likely that these tapered surfaces contact in an inclined manner because of the dimensions for the sliding movements, etc., and the dimensional tolerances, etc.
Hence, it is further suitable that one of the portion, with which the swash plate contacts the aligning member, and the portion, with which the aligning member contacts with the swash plate, is formed as a minor-diameter tapered surface on an inner side of the swash plate, and that the other one of them is formed as a convexed curved surface.
Thus, the minor-diameter side of the tapered surface is positioned on the inner side of the swash plate, not only it is likely to fill up the clearances between the swash plate and the other members, but also it is easy to carry out the processing so that it is possible to realize the reduction of the production cost.
In a case where the driving shaft is the other member, that is, in a case where the swash plate contacts directly with the driving shaft, the through hole, into which the driving shaft is fitted, is formed through in the swash plate like the compressor set forth in the aforementioned publication. This through hole is formed so as to permit an inclination-angle displacement of the swash plate over an entire control range about a swing-shaft center, which is set beyond a side of the driving shaft, side which faces the hinge mechanism, while interposing a shaft center therebetween. Since it is comparatively difficult to form such a through hole with a high accuracy, the present invention greatly exhibits the effect especially in this case. The aligning member is fitted with the driving shaft.